In displays of the type of Thin Film Transistor-Liquid Crystal Display (TFT-LCD), each pixel unit has a corresponding TFT on an array substrate, a gate of the TFT is connected to a scanning line (also referred to as row scanning line) in a horizontal direction, a drain of the TFT is connected to a data line in a vertical direction, and a source of the TFT is connected to a pixel electrode. During displaying of a display, if a sufficient positive voltage is applied on the scanning line of a row in the horizontal direction, all of TFTs of the row are turned on under the control of the gates of TFTs, the pixel electrodes corresponding to the TFTs of the row at this moment will be connected to the data lines in the vertical direction respectively, and thus display signal voltages transmitted on the data lines will be written into the pixel electrodes respectively, so that, for one of the pixel electrodes, the liquid crystal in the pixel unit region corresponding to the pixel electrode is in turn controlled to achieve a different optical transmittance, thus achieving the control of the grayscale and/or color displayed by the pixel units.
At present, a driving circuit of the TFT-LCD panel is mainly implemented by attaching Integrated Circuit (IC) on the outer edge of the panel, and the IC is generally manufactured by using a silicon chip constructed by CMOS. Since the attached IC occupies a certain area and the connection lines for connecting IC also occupy a certain area, the panel thus obtained has a low integration level and a large area, which goes against the miniaturization and thinning of the display apparatus.
In order to solve such a problem, Gate Driver on Array (GOA) technology has been developed, which manufactures the Gate Driver IC of the TFT-LCD directly on the array substrate so as to replace the driving IC attached on the outer edge of the panel and manufactured by using the silicon chip. Since such technology can manufacture the driving circuit directly on the array substrate, the attaching of IC on the outer edge of the panel and the wiring are not required, thus reducing the manufacturing procedure of the panel and decreasing the cost of products while increasing the integration level of the TFT-LCD panel to make the panel thinner. There are many methods for implementing integrated gate driver registers in the prior art, a register may include different numbers of transistors and capacitors and the commonly used structures may include for example 12T1C (a structure including 12 Thin Film Transistors and 1 coupling capacitor), 9T1C, 13T1C and the like, and pulse shifting is achieved in the register by at least a group of clock signals, a pulling-up transistor, a pulling-down transistor and an output transistor.
Since the registers in GOA have a high integration level and are sensitive to noise, and since the duty ratio of the pulling down (PD) voltage generated by a CLK signal (clock signal) or a CLKB (inverse clock signal, that is, a signal inverse to the clock signal) signal is only 50% in the prior shift register, a pulling-down transistor only can discharge the output noise (i.e. the noise in the output) during half of a frame. If the output noise fails to be effectively suppressed in the shift register circuit at a certain stage and becomes the input to the shift register circuit at a next stage, the output noise will be amplified stage by stage. Specially, after the shift register circuit operates under a high temperature circumstance for a period of time, the noise will be more apparent and even may cause a plurality of outputs, causing turbulence in the display of TFT-LCD.